Performance measures.

<p>Accuracy, reaction times, and the percentage of trials on which participants corrected their responses immediately after an error (means ± standard errors) are shown for each task and beverage condition. The Stroop interference effect is indicated by lower accuracy and slower reaction times to conflict-inducing incongruous (INC) stimuli overall. Alcohol did not affect RTs, but participants responded less accurately and made more corrective responses on INC trials when intoxicated. Significant alcohol vs. placebo comparisons for each condition are marked, *p<0.05.</p

Group-average maps of event-related theta source power estimates in 320–470 ms time window.

<p>Event-related theta power is elicited in the fronto-parieto-cingulate network with the ACC as the strongest estimated source, and is attenuated by intoxication (<i>white arrows</i>). The color scale depicts baseline-corrected noise-normalized source power expressed in arbitrary units. The bottom row shows conflict–related theta power (INCONG - CONG contrast) for both beverage conditions. The color scale denotes differential baseline-corrected source power estimates, with red-yellow indicating stronger theta power to INCONG. Conflict-related theta is attenuated by intoxication in the right prefrontal (<i>cyan arrow</i>) and ACC (<i>orange arrow</i>) cortices. CONG stimuli elicited stronger theta in the motor -related medial cortex due to motor preparation at this latency.</p

Group-average timecourses of event-related theta source power estimates in selected regions of interest.

<p>While alcohol reduces event-related theta power overall, attenuation of the conflict-related theta (INCONG vs. CONG contrast) is particularly prominent in ACC, with contributions from lateral fronto-parietal areas. Direct comparison of the beverage effects on conflict-related theta reached significance as indicated by arrows, *p<0.05, **p<0.01. Horizontal bars indicate the three time windows for which power was averaged and entered into statistical analysis. The y-axis depicts baseline-corrected noise-normalized source power expressed in arbitrary units. ACC: anterior cingulate cortex; IFJ: inferior frontal junction; IFG: inferior frontal gyrus; SFG: superior frontal gyrus; PAR: parietal cortex.</p

Grand averages of event-related EEG power at the frontal (Fz) electrode.

<p>a) Time-frequency plots of total event-related power expressed as the relative percentage change from the power in the baseline (−250 to 0 ms) for each frequency. Four task conditions (rows) are shown for placebo and alcohol sessions. Most pronounced beverage and task effects were observed in the theta band. b) Group averaged total event-related power in the theta frequency band at the Fz electrode. Horizontal bars indicate the three time windows for which power was averaged and entered into statistical analysis. Alcohol decreased total event-related theta power overall. Conflict-related increase in theta power was significant in the late time window only under placebo.</p

Summary of ANOVAs of event-related theta for different ROIs (MEG), and Fz and Cz electrode locations (EEG).

<p>Included are the results for main effects and interactions of Condition and Beverage, conflict-related theta power (INCONG - CONG contrast) for alcohol and placebo, and beverage effect on conflict-related theta power (Alc - Plac x INCONG - CONG interaction).</p><p>ACC: anterior cingulate cortex; IFJ: inferior frontal junction; IFG: inferior frontal gyrus; SFG: superior frontal gyrus; PAR: parietal cortex. Conflict-related theta power is larger to INCONG than CONG in all cases. Significance level is indicated as follows:</p>*<p>p<0.05,</p>**<p>p<0.01,</p>***<p>p<0.001,</p>****<p>p<0.0001;</p>†<p>p<0.1.</p

Group-average timecourses of response-locked theta source power estimates in the left ACC and MOT areas.

<p>Time 0 ms corresponds to the button press. The time window immediately preceding motor responses is indicated by a horizontal bar. During this time, only ACC showed sensitivity to conflict with stronger theta on INCONG than CONG trials during placebo (* p<0.02), suggesting the ACC engagement in response selection and execution. Alcohol attenuated pre-response theta overall. The y-axis depicts baseline-corrected noise-normalized source power expressed in arbitrary units.</p

Regional Parcellation Coding Scheme.

<p>Regional Parcellation Coding Scheme.</p

The distribution characteristics of affected white matter pathways.

<p>WM fiber pathways intersected by the rod were pooled across all N = 110 subjects and examined for a) the relative lengths (w_ij) of affected pathways and b) the relative percentages of lost fiber density (g_ij); c) the bivariate distribution of g_ij versus w_ij indicating that local fiber pathways were affected, <i>e.g.</i> relatively short pathways proximal to the injury site, as well as damaging dense, longer-range fiber pathways, <i>e.g.</i> innervating regions some distance from the tamping iron injury (see “<i>Calculation of Pathology Effects upon GM/WM Volumetrics</i>” for further details).</p

Mean connectivity affected by the presence of the tamping iron combined across subjects.

<p>The lines in this connectogram graphic represent the connections between brain regions that were lost or damaged by the passage of the tamping iron. Fiber pathway damage extended beyond the left frontal cortex to regions of the left temporal, partial, and occipital cortices as well as to basal ganglia, brain stem, and cerebellum. Inter-hemispheric connections of the frontal and limbic lobes as well as basal ganglia were also affected. Connections in grayscale indicate those pathways that were completely lost in the presence of the tamping iron, while those in shades of tan indicate those partially severed. Pathway transparency indicates the relative density of the affected pathway. In contrast to the morphometric measurements depicted in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037454#pone-0037454-g002" target="_blank">Fig. 2</a>, the inner four rings of the connectogram here indicate (from the outside inward) the regional network metrics of betweenness centrality, regional eccentricity, local efficiency, clustering coefficient, and the percent of GM loss, respectively, in the presence of the tamping iron, in each instance averaged over the N = 110 subjects.</p

Healthy region-specific graph theoretical metrics, the effects of systematic lesions, and the difference between the observed and simulated tamping iron lesions.

<p>A) Cortical maps of regional graph theoretical properties. Regions affected by the passage of the tamping iron include those having relatively high betweenness centrality and clustering coefficients but relatively low mean local efficiency and eccentricity. B) A cortical surface schematic of the relative effects of systematic lesions of similar WM/GM attributes over the cortex for both network integration (i) and segregation (ii). For each mapping, colors represent the Z-score difference between systematic lesions of that area relative the average change in integration taken across all simulated lesions. C) Cortical maps of the differences/similarity between the effects on integration and segregation observed from the tamping iron lesion with that of each simulated lesion. Here black is most similar (e.g. the observed lesion is most similar to itself) whereas white is least similar to (e.g. most different from) the tamping iron's effects on these measures of network architecture.</p